During drilling or production operations of a reservoir, the compositions of downhole fluids often affect the drilling process because the thermophysical properties of the downhole formation fluids vary with pressure, temperature, and chemical composition. Downhole formation fluids can have many properties, such as viscosity, density, thermal conductivity, heat capacity, and mass diffusion. Each of these properties can at least partially govern transportation and mobility of crude oils, including high viscosity crude oils, and can consequently impact the recovery process. High viscosity hydrocarbon fluid production may require external heating methods to reduce the viscosity of the fluids and enable fluid transport from the reservoir to the well location. Efficiency of production can be dependent upon the external heating power and thermal energy transport within a limited time interval. Higher heat capacity hydrocarbon fluids may require more thermal energy to effectively reduce their viscosity. It is desirable to be able to measure the heat capacity of formation fluids either during wireline logging services or the production process.
Formation fluids may have similar specific heat capacities but different viscosity, thermal conductivity, density, and mass diffusivity. Knowing these thermophysical properties of formation fluids can at least partially enable optimization of downhole tools and their long-term reliability or production optimization. Presently, most thermophysical properties of formation fluids are typically measured from samples that are taken downhole and then analyzed in a lab, which can take days, or even months. The potential phase transition may reduce the accuracy of any measurement due to the passage of time since sample collection and environmental changes at the collection point(s) which can occur over time. In-situ measurement of these parameters can improve accuracy of measurement and improve tool design and well production efficiency.